Costs Associated with Failure of Vancomycin Treatment for Pneumonia and Bacteremia Due to Methicillin-Resistant Staphylococcus aureus.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) infections are associated with high rates of mortality and morbidity. Vancomycin is widely used for the treatment of pneumonia and bacteremia due to MRSA, despite treatment failure rates between 21% and 50%. Given the high rates of treatment failure with vancomycin, it is hypothesized that such failure may add a substantial burden to the health care system. OBJECTIVES: To estimate the hospital costs for patients treated with vancomycin for MRSA pneumonia and/or bacteremia, comparing costs between those who experienced treatment failure and those who experienced treatment success. METHODS: This retrospective cohort study involved patients admitted to a Canadian hospital between 2014 and 2018 with MRSA pneumonia and/or bacteremia who were treated with vancomycin. Direct and indirect hospital costs and additional clinical data were obtained from the hospital database. All costs were inflated to 2024 Canadian dollars using the Consumer Price Index. A generalized linear model was used to estimate the adjusted difference in hospital costs between patients with and without treatment failure. RESULTS: A total of 128 patients were included in the cohort, of whom 43 (34%) were identified as having treatment failure. Treatment failure was associated with significantly higher costs than treatment success, with an adjusted mean difference in total cost of $43 082 (95% confidence interval $2065 to $84 098). Those with treatment failure had higher rates of vasopressor use, greater need for intensive care, higher sequential organ failure assessment scores, greater need for mechanical ventilation, and higher rates of nephrotoxicity. CONCLUSIONS: Failure of vancomycin treatment for MRSA pneumonia and/or bacteremia significantly increased hospital costs.